Pain is the mental manifestation of a neurological response to various physiological and psychological ailments. Sometimes pain corresponds to or serves as a warning of physical damage or biological dysfunction. Sometimes pain is a characteristic of a biological transition. In any event, control and alleviation of pain has been an important function of medicine for as long as medical practitioners have existed. The most common pain-control methods employ bio-active chemical agents that act to block neurotransmission pathways within the body. However, sometimes such chemical agents are ineffective or produce unacceptable side effects. Consequently, neuromuscular electrical stimulation (NMES) has also been employed to alleviate pain.
Two types of NMES that can be used to alleviate pain are burst-modulated alternating current (“BMAC”) and pulsed current (“PC”). BMAC is commonly applied by use of interferntial current or “Russian current” stimulators, whereas PC is commonly applied by a transcutaneous electrical nerve stimulation (“TENS”) device. In the application of BMAC, two medium-frequency (i.e., 1 KHz-100 KHz) carrier waves are caused to interfere with each other, resulting in an interference current frequency that is equal to the difference between the interfering frequencies. For example, if current A is at 4000 Hz and current B is at 3900 Hz, their interaction would produce an interference current having a beat frequency of 100 Hz that is carried on a 3950 Hz frequency carrier wave. The advantage to BMAC is that it can be used to apply electrical stimulation to much deeper tissues than PC. A TENS device never employs a carrier wave, and it produces PC electrical stimulation at much lower frequencies (i.e., typically within the range of 2-150 Hz) than are employed in the application of BMAC. PC electrical stimulation is thought to work by blocking pain impulses from the brain, whereas BMAC can heal damaged tissues.
TENS is generally employed for the alleviation of pain by application to muscles through electrodes that are attached to or placed upon the surface of the skin. Most commonly, a TENS unit is attached to one or more pairs of electrodes by wires, and these electrodes are adhesively attached to the skin of the patient. A therapist controls the operation of the device to achieve the desired results.
Notes on Construction
The use of the terms “a”, “an”, “the” and similar terms in the context of describing the invention are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising”, “having”, “including” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. The terms “substantially”, “generally” and other words of degree are relative modifiers intended to indicate permissible variation from the characteristic so modified. The use of such terms in describing a physical or functional characteristic of the invention is not intended to limit such characteristic to the absolute value which the term modifies, but rather to provide an approximation of the value of such physical or functional characteristic. All methods described herein can be performed in any suitable order unless otherwise specified herein or clearly indicated by context.
The use of any and all examples or exemplary language (e.g., “such as”) herein is intended merely to better illuminate the invention and not to place a limitation on the scope of the claimed invention. Nothing in the specification should be construed as indicating any element as essential to the practice of the invention unless so stated with specificity.
As used herein, the term “lower”, when used to describe a relative location on or with respect to a portable TENS device having integral electrodes that is used to apply NMES through the skin of a user, refers to a direction or location adjacent to or nearer to the skin of the user when the device is in use.